Rotor blades of wind turbines are mounted with their longitudinal axis extending transversely to the axis of the drive shaft and the hub of the wind turbine. The pitch of the rotor blades may be adjusted by rotating the rotor blades about their longitudinal axis, whereby their individual aerodynamic properties and performance are modified and the overall performance of the wind turbine is adapted to the actual conditions such as wind speed and load.
Rotor blades of wind turbines may also have movable parts such as one or more flaps along their trailing edge. Such movable parts may be moved individually to further modify and improve the aerodynamic properties of the rotor blade. Such movable parts can be actuated to move by means of an actuator situated within the blade near the movable part or preferably in the hub or in the root of the blade, i.e. near the hub, or possibly in the nacelle of a wind turbine.
Electrically conductive objects such as metal components in or at a rotor blade may potentially attract lightning and lightning strokes can be destroying and should be avoided. This applies in particular to actuating rods, shafts and wires but also to electrical cables and conductors.